1. Field
Aspects of the present invention generally relate to a liquid ejection head and a method for manufacturing a liquid ejection head.
2. Description of the Related Art
A liquid ejection head used in, for example, ink jet printing apparatuses includes a print element board and an electric wiring board. FIG. 2A illustrates a print element board of a liquid ejection head. The print element board includes a base plate 1 and an energy generating device 15 that generates energy for ejecting droplets of liquid. The base plate 1 has a supply port 11 formed therein. The supply port 11 supplies liquid to the energy generating device 15. In addition, the base plate 1 includes an ejection port forming member 12 for forming an ejection port 13. The ejection port 13 ejects droplets of the supplied liquid.
As described in Japanese Patent Laid-Open No. 2007-307833, electric power is supplied from an external electric wiring board to the energy generating device 15 using an electrode pad (not illustrated) of the print element board and a bump 7 formed on the electrode pad. The electrode pad is electrically connected to the energy generating device. Electric power is supplied from the electric wiring board by connecting the bump 7 to the electric wiring board using an interconnecting wire.
For example, the bump 7 is formed by plating, such as gold plating. FIG. 2B is a cross-sectional view taken along a line IIB-IIB of FIG. 2A, that is, an enlarged view of the bump formed by plating. The bump 7 is formed on an electrode pad 3 made of, for example, aluminum. An insulation layer 2 made of, for example, SiO2 is disposed between the base plate 1 and the electrode pad 3. The electrode pad 3 is disposed between protective layers 4 made of P—SiN. In order to increase adhesiveness between the electrode pad 3 and the bump 7 and prevent a decrease in connection reliability caused by mutual metal diffusion, a diffusion prevention layer 5 is formed between the electrode pad 3 and the bump 7.